Field of the Invention
The invention relates to an image pickup apparatus such as a digital camera which includes a movable flash light emission unit.
Description of the Related Art
Some small-sized digital cameras having a large-diameter lens barrel include a pop-up-type strobe unit for the purpose of preventing so-called “vignetting” in which strobe light is blocked at a front edge of the lens barrel and does not reach a subject. Such a pop-up-type strobe unit has a movable member having a strobe light emission unit which moves between a housing position at which the movable member is inside a camera body part and a light emission position at which the movable member projects from the camera body part. As a mechanism which moves the movable member from the housing position inside the camera body part to the light emission position, there is a pop-up mechanism which uses two rotation shafts, which has an advantage that a housing space of the movable member can be smaller in response to demands for small-sized cameras. With the mechanism using the two rotation shafts, the strobe light emission unit is moved to a subject side in the optical axis direction of the lens barrel in addition to a camera-height direction, and to thereby avoiding the vignetting while suppressing an amount of pop-up.
As a contact-type means for detecting a light emission position of the strobe light emission unit, a push switch or the like is used. In this contact type, the switch is pressed when the strobe light emission unit is in a housing position and in an ON state, and thus the unit is controlled to be in a non-light-emissive state. In addition, when the strobe light emission unit is in a light emission position, it is separated from the switch and in an OFF state, and thus is controlled to be in a light emissive state. However, with respect to such a contact-type detection switch, there is generally a limit on timings at which ON and OFF states are switched when a position of the strobe light emission unit is detected. That is to say, a case in which, in the course of moving the strobe light emission unit from the housing position to the light emission position in such a pop-up mechanism that uses two rotation shafts, the movement is stopped by a photographer or the like is assumed. In this case, there is a possibility of the detection switch switching to the OFF state and the unit being switched to the light emissive state even when the strobe light emission unit does not project from the camera body part. For this reason, so-called “burning” occurs in the camera body part.
On the other hand, as a non-contact-type means for detecting a light emission position of a strobe light emission unit, a magnet and a magnetic sensor are used (refer to Japanese Patent Laid-Open No. 2009-116321). In the non-contact-type detection method, changes in a distance between the magnet and the magnetic sensor in a housing position and a light emission position of the strobe light emission unit are detected. For example, when the strobe light emission unit is in the housing position, the magnetic sensor included in the camera body part comes close to the magnet included in the strobe light emission unit, and thus the unit switches to an ON state and is controlled to be in a non-light-emissive state. In addition, when the strobe light emission unit is in the light emission position, the magnetic sensor and the magnet are separated from each other, and the unit switches to an OFF state, and is controlled to be in a light emissive state.
In the related art disclosed in Japanese Patent Laid-Open No. 2009-116321, a magnet is disposed inside a strobe case near a strobe light emission unit in a pop-up-type strobe unit which uses two rotation shafts. Thus, when the distance between the strobe light emission unit and a magnetic sensor is excessively long, a detection signal turns off before the strobe light emission unit projects from a camera body part, resulting in a light emissive state. That is to say, when a movement of the strobe light emission unit from the housing position to the light emission position is stopped by a photographer in the course of the movement, the state becomes a detection-off state even though strobe light is being radiated to the inside of the camera body part, and is switched to a light emissive state. Therefore, there is a possibility of burning occurring in the camera body part. In addition, there is a method of delaying a timing at which a detection signal of a magnetic sensor turns off by raising sensitivity of the magnetic sensor. In this case, there is a possibility of an erroneous detection occurring due to another magnetized metal component or the like.
Therefore, it is desirable to increase the size of a magnet and bring the magnet and a magnetic sensor close to each other in a housing state of a strobe light emission unit. If a distance between the magnet and the magnetic sensor can be shortened in the housing state, a degree of freedom in disposing the magnetic sensor also increases.